Gasket



G. T. BALFE Aug. l5, 1939.

GASKET Filed Jan. 24, 1938 gmc/who@ Patented Aug. l5, 17939 UNITED STATES PATENT OFFICE GASKET George T. Balie, Detroit, Mich., assigner to Detroit Gasket & Mfg. Company, Detroit, Mich., a corporation of Michigan Application January 24, 1938, Serial No. 186,700 1 Claim. (Cl. 288-33) 'Ihis invention relates to gaskets, and particuformed which is not affected by the high temlarly gaskets of the insulator type useful at the peratures to which insulator gaskets are subjoint between the carburetor and the manifold of jected.

an internal combustion engine to prevent over- 'Referring to the drawing: 5 heating of the carburetor. Figure 1 is a diagrammatic view of a method 5 Numerous gaskets have been proposed for this employed for making the gasket; purpose but either due to lack of required resist- Figure 2 is a perspective view of an insulator ance or inability to seal irregularities in the joint gasket made in accordance with this invention; surfaces, nearly all of these products include a and i core gasket and separate special gaskets on each Figure 3 shows the gasket applied at the joint l0 side of the core for contact with the joint surfaces between a carburetor and the manifold.

to seal the same. Referring to Figure 2, the gasket I0 is shown The object of this invention is to eliminate as of conventional shape for use between the such built up gaskets, and to provide a single inmanifold and carburetor of an internal combustegral insulator gasket. tion engine assembly illustrated in Figure 3. 0f 15 The gasket of the present invention consists course, this product can be made in various of a mixture of a synthetic resin of the heat hardshapes and sizes as required and may be generenable type and an insulating material such as ally used to seal joints.

asbestos in nely divided state. This gasket has In preparing the gasket, and referring to Figthe required insulative properties and is charure 1, any suitable insulating material, preferably 20 acterized by resistance to heat, water, gas and asbestos, in nely divided or powdered state is oil. The percentage relationship of insulating thoroughly mixed in a mixing machine Il with a* material to resin and the density of the gasket potentially reactive synthetic resin, likewise in are such, that the gasket is compressible, .whereby ilnely divided or powdered state. The resin is it is self-sealing and is non-absorbent and impreferably of the phenol formaldehyde type but 25 permeable to liquids and gases. At the same time practically any of the heat hardenable resins the gasket is rigid enough to be machined and is available may be used, bearing in mind the final resistant to fracture when compressed between properties which the gasket need possess. The and in direct contact with the surfaces lof the mixture is then passed through a suitable mill I2 joint, comprising a pair of rotating rolls which become 30 Gaskets of synthetic resin and insulating maheated as they compress the mixture between terial are described in the patent to Baekland, them. 'I'his heating will serve-to reduce the 941,605, November 30, 1909, but there is no teach- A moisture content of the asbestos, but is insuiliing of an insulator gasket having the qualities cient to affect the resin. The mixture issues from above defined, all of which are essential for a the millv in the form 0f relatively thin Compressed 35 satisfactory product, f sheets or strips. These compressed cakes of the I have discovered that certain critical condiresin-asbestos mixture are then ground to a very tions must be observed in ,the manufacture of a iine condition in any suitable type 0f mill aS suitable insulator gasket in order that it will have shown at I3; an additional amount of resin being 40 the above desired properties. For example, the added as required. The mixture is then com- 40 .asbestos must be in finely ground condition and pressed in a cold mold I4 to the shape shown in its admixtue with the potentially reactive resin Figure 1, or other desired shape, and the selfmust be quite thorough and the resinA must like- Sustaining Product iS then Itreated in the Oven l5 wise be in finely divided condition. Furthermore, t0 Cure the resin and ferm the nal gasket:Y If

there are definite critical limits as to the ratio of required. machining of the gasket may be accom- 45 the content ofresin and insulating material. plished, but this is not always necessary.

Also, in making the product, the mixture of resin As 4an example of the critical range of perand insulating material must rst be compressed enlage relatiOnShlp 0f the Constituents 0f the in the cold under a critical pressure to form a mixture, I have discovered that the ratio of fineproduct which is self-sustaining and which on ly divided asbestos to finelyl divided resin should 5o heating to cure the resin will have the desired be between about 4:1 to 3:2. In the case of a nal qualities. That is to say, when the molded product having a ratio'of asbestos to resin of product of this invention is subjected to heat to about 3 to 2, a pressure of 40 tons in the molding effect curing of the resin, a non-absorbent, imapparatus Il has been found satisfactory. The

permeable, strong and compressible gasket is density of the gasket can, of course, be controlled 55 by the molding pressurek which is relatively high, but the final product in all cases is a compact body, is impermeable and non-absorbent to liquids and gases; and the nbres or other insulating material are strongly bonded.

In some cases and preferably at the time the resin is added at the second stage. of the method,

i. e., to the grinding mill I3, a small percentage of lubricant, e. g., 1% of calcium stearate, may

be added,'but this is not always required.

By having a strong gasket possessedof the desired compressibility, the use of superposed gaskets is eliminated and the gasket has the property of self-sealing, i. e., conforming to any irregularities in the joint surfaces.

Insulator gaskets usually have a substantial thickness as shown, for example and the gasket of this invention may be made of any required dimension.

The gasket and its method of manufacture may be modied in various ways, but all changes within the scope of the invention are considered to be comprehended in the appended claim.

I claim:

An insulator gasket of integral, unitary construction suiliciently compressible to provide a good seal and impermeable to water, gas and oil, comprising a mixture of compressible insulating material, suchlas asbestos, in finely divided state having uniformly distributed therethrough a heat-hardened synthetic resin, the relationship of insulating material to resin being of the order between 4:1 and 3:2 and the mixture being pressed to shape under a compression suicient to provide a self-sustaining form and to impart the desired gasket strength and density and being finally cured by heat treatment.

' GEORGE T. BALFE. 

